Cyclical unemployment occurs when there are too few jobs to employ everyone who wants to work. This is what happens during a recession, and it’s the worst.

Structural unemployment is caused by changes that affect the labor market, such as improved technology or shifting consumer preferences. New opportunities are created, but the changes cause some people to lose jobs.

Frictional unemployment occurs as part of normal turnover in the labor market; someone who is unemployed takes time to find a desirable job or an employer waits for the best applicants.

U-5 Total unemployed, plus discouraged workers, plus all other persons marginally attached to the labor force, as a percent of the civilian labor force plus all persons marginally attached to the labor force

U-6 Total unemployed, plus all persons marginally attached to the labor force, plus total employed part time for economic reasons, as a percent of the civilian labor force plus all persons marginally attached to the labor force

Persons marginally attached to the labor force are those who currently are neither working nor looking for work but indicate that they want and are available for a job and have looked for work sometime in the past 12 months. Discouraged workers, a subset of the marginally attached, have given a job-market related reason for not currently looking for work. Persons employed part time for economic reasons are those who want and are available for full-time work but have had to settle for a part-time schedule. Updated population controls are introduced annually with the release of January data.